Gravel Road Calculator
A road is a driveway scaled up — longer, wider, and worth computing in layers. Run this tool once per layer (6" base, then 2" surface), pre-set here to crusher run at base depth. At road lengths, rounding errors become truckloads: measure carefully.
Roads: layers, crown, and maintenance
A private road is a driveway that must survive delivery trucks and rain. The standard build: subgrade shaped with a crown (center 2–4" above edges), a 6"+ compacted dense-graded base, and a 2" wearing surface — each computed as its own pass of the calculator.
Worked example: a quarter-mile lane (1,320 ft) 10 ft wide. Base: 13,200 ft² × 0.5 ft = 6,600 ft³ = 244 yd³ of crusher run ≈ 392 tons. Surface: 13,200 × 0.167 = 2,200 ft³ = 81.5 yd³ of #67 ≈ 111 tons. Budget the 10–15% compaction buffer — this is multi-truckload territory where it genuinely adds up.
Gravel road FAQ
How much gravel do I need for a private road?
A quarter-mile lane, 10 feet wide, with a 6-inch compacted base plus 2-inch surface needs roughly 244 cubic yards of base (about 392 tons of crusher run) plus 82 cubic yards of surface (about 111 tons) — around 500 tons total. Compute your own length in two runs (base and surface) with the calculator above; long roads justify getting the number right.
Why do gravel roads need a crown?
A crown — the center standing 2–4 inches higher than the edges — sheds water to the sides instead of letting it sit on the road. Standing water softens the base, forms potholes, and is the fastest way a gravel road fails. Shape matters as much as stone.
What's the best gravel for a road surface?
A dense-graded angular stone — crusher run or a state-approved road base — for the structural layers, often topped with a cleaner stone. The base carries load; the surface drains and can be graded. Round river rock belongs nowhere in a road.